IBM grafts old AIX 5.3 onto shiny new Power7+ servers

Big Blue stopped selling the venerable AIX 5.3 release of its Unix operating system nearly two years ago and pulled the plug on normal support nearly a year ago, but it lives on atop the new Power7+ servers that the company launched as 2012 came to a close.

AIX 5.3, which was probably the most popular release of AIX in the history of IBM's Unix systems business, came out in August 2004 for Power3, Power4, and Power5 systems as well as PowerPC blade servers. It was timed more or less with dual-core Power5 processors, and the popularity of those machines and the wide acceptance by independent software providers gave IBM the momentum to take on Hewlett-Packard and Sun Microsystems in the Unix racket. AIX 5.3 is also the last release of IBM's Unix to support a 32-bit kernel alongside a 64-bit kernel.

IBM has committed to support AIX releases for at least a decade, and as you can see here for the 5.3 release, the venerable OS still has some legs yet. But those last couple of years of support require extra fees, what IBM calls service extension.

In this case, normal AIX 5.3 support under a software maintenance contract ended on April 30 last year, and if you want to run AIX 5.3 on the Power7+ systems, you need to have this supplemental service extension contract.

IBM does not publish pricing for it, but presumably service extension is more expensive than the standard software maintenance support contract (SWMA, pronounced "swamma," in IBMese), which ranges from a low of $75 per core per year on an AIX 7.1 Express license on a small system to $1,013 per core per year on a large system. This works out to 25 per cent of the license cost per core for AIX 7.1. Support prices for AIX 5.3 are in the same range, but tiered slightly differently.

With the latest update to AIX 5.3, which is Technology Release 12 Service Pack 7 technically, the old operating system kernel has been modified to run on the Power 770+ and Power 780+ enterprise-class servers that were announced on October 3 last year as well as the Flex System p260+ two-socket server nodes that were announced on November 13.

The Power7+ chips will not be put into the high-end, 256-core Power 795 machines, according to IBM, although that could change based on customer demand if enough AIX shops say they want to get all of those neat hashing, encryption, and memory encryption accelerators that are in the Power7+ chips as well as the 10MB per core of L3 cache, which is a factor of 2.5 times larger than that in the Power7 chips used in the Power 795 server.

A plus sized Power 795 would seem to be in order, but IBM told El Reg last year that customers should not expect a new big bad box until the Power8 generation, perhaps in late 2014 or early 2015 if history is any guide. In the server chip business, history has had a few drinks and sometimes gets the roadmap upside down.

Power7+ chips will no doubt make their way into other Flex System nodes as well as entry and midrange Power Systems iron within the next few months. IBM is also working on Power7+ variants that will "double stuff" two down-clocked Power7+ chips into a single socket to increase the core, thread, and cache count per socket to take on x86 chips from Intel and Advanced Micro Devices.

Given that AIX 5.3 is expected to get extended support until at least August 2014, these forthcoming machines, it is highly likely that these Power 710+, Power 720+, Power 730+, Power 740+, and Power 750+ will also support AIX 5.3 with Technology Release patches.

The funny bit, of course, is that when AIX 5.3 came out in August 2004, the top-end, rack-sized p5 595 had 32 sockets and 64 threads running at 2.3GHz as its largest system image.

With a double-stuffed Power7+ chip, you will be able to cram 32 cores and 64 threads, perhaps running at a much higher 3GHz or higher, into a two-socket box the size of a pizza box. And the pizza box will probably deliver much more performance thanks to all that extra cache and accelerators and the many architectural and system enhancements that have taken place in the past decade. ®